nervous about potentially miscarrying

Cassie
My first pregnancy was a year ago and I ended up miscarrying at about 11 weeks. 
I'm at six weeks and super happy about being pregnant again. I Foyt want this one to end like the last. What are some potential signs that I could have a lifeless fetus inside me? Is there any way to tell? 
My first doctors appt is in a week and a half (likely won't have an ultrasound at this appt).